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  <div class="section" id="operating-system-utilities">
<span id="os"></span><h1>Operating System Utilities<a class="headerlink" href="#operating-system-utilities" title="Permalink to this headline">¶</a></h1>
<dl class="cfunction">
<dt id="Py_FdIsInteractive">
int <tt class="descname">Py_FdIsInteractive</tt><big>(</big>FILE<em> *fp</em>, const char<em> *filename</em><big>)</big><a class="headerlink" href="#Py_FdIsInteractive" title="Permalink to this definition">¶</a></dt>
<dd>Return true (nonzero) if the standard I/O file <em>fp</em> with name <em>filename</em> is
deemed interactive.  This is the case for files for which <tt class="docutils literal"><span class="pre">isatty(fileno(fp))</span></tt>
is true.  If the global flag <tt class="xref docutils literal"><span class="pre">Py_InteractiveFlag</span></tt> is true, this function
also returns true if the <em>filename</em> pointer is <em>NULL</em> or if the name is equal to
one of the strings <tt class="docutils literal"><span class="pre">'&lt;stdin&gt;'</span></tt> or <tt class="docutils literal"><span class="pre">'???'</span></tt>.</dd></dl>

<dl class="cfunction">
<dt id="PyOS_GetLastModificationTime">
long <tt class="descname">PyOS_GetLastModificationTime</tt><big>(</big>char<em> *filename</em><big>)</big><a class="headerlink" href="#PyOS_GetLastModificationTime" title="Permalink to this definition">¶</a></dt>
<dd>Return the time of last modification of the file <em>filename</em>. The result is
encoded in the same way as the timestamp returned by the standard C library
function <tt class="xref docutils literal"><span class="pre">time</span></tt>.</dd></dl>

<dl class="cfunction">
<dt id="PyOS_AfterFork">
void <tt class="descname">PyOS_AfterFork</tt><big>(</big><big>)</big><a class="headerlink" href="#PyOS_AfterFork" title="Permalink to this definition">¶</a></dt>
<dd>Function to update some internal state after a process fork; this should be
called in the new process if the Python interpreter will continue to be used.
If a new executable is loaded into the new process, this function does not need
to be called.</dd></dl>

<dl class="cfunction">
<dt id="PyOS_CheckStack">
int <tt class="descname">PyOS_CheckStack</tt><big>(</big><big>)</big><a class="headerlink" href="#PyOS_CheckStack" title="Permalink to this definition">¶</a></dt>
<dd>Return true when the interpreter runs out of stack space.  This is a reliable
check, but is only available when <tt class="xref docutils literal"><span class="pre">USE_STACKCHECK</span></tt> is defined (currently
on Windows using the Microsoft Visual C++ compiler).  <tt class="xref docutils literal"><span class="pre">USE_STACKCHECK</span></tt>
will be defined automatically; you should never change the definition in your
own code.</dd></dl>

<dl class="cfunction">
<dt id="PyOS_getsig">
PyOS_sighandler_t <tt class="descname">PyOS_getsig</tt><big>(</big>int<em> i</em><big>)</big><a class="headerlink" href="#PyOS_getsig" title="Permalink to this definition">¶</a></dt>
<dd>Return the current signal handler for signal <em>i</em>.  This is a thin wrapper around
either <tt class="xref docutils literal"><span class="pre">sigaction</span></tt> or <tt class="xref docutils literal"><span class="pre">signal</span></tt>.  Do not call those functions
directly! <tt class="xref docutils literal"><span class="pre">PyOS_sighandler_t</span></tt> is a typedef alias for <tt class="xref docutils literal"><span class="pre">void</span>
<span class="pre">(*)(int)</span></tt>.</dd></dl>

<dl class="cfunction">
<dt id="PyOS_setsig">
PyOS_sighandler_t <tt class="descname">PyOS_setsig</tt><big>(</big>int<em> i</em>, PyOS_sighandler_t<em> h</em><big>)</big><a class="headerlink" href="#PyOS_setsig" title="Permalink to this definition">¶</a></dt>
<dd>Set the signal handler for signal <em>i</em> to be <em>h</em>; return the old signal handler.
This is a thin wrapper around either <tt class="xref docutils literal"><span class="pre">sigaction</span></tt> or <tt class="xref docutils literal"><span class="pre">signal</span></tt>.  Do
not call those functions directly!  <tt class="xref docutils literal"><span class="pre">PyOS_sighandler_t</span></tt> is a typedef
alias for <tt class="xref docutils literal"><span class="pre">void</span> <span class="pre">(*)(int)</span></tt>.</dd></dl>

</div>
<div class="section" id="system-functions">
<span id="systemfunctions"></span><h1>System Functions<a class="headerlink" href="#system-functions" title="Permalink to this headline">¶</a></h1>
<p>These are utility functions that make functionality from the <a title="Access system-specific parameters and functions." class="reference external" href="../library/sys.html#module-sys"><tt class="xref docutils literal"><span class="pre">sys</span></tt></a> module
accessible to C code.  They all work with the current interpreter thread&#8217;s
<a title="Access system-specific parameters and functions." class="reference external" href="../library/sys.html#module-sys"><tt class="xref docutils literal"><span class="pre">sys</span></tt></a> module&#8217;s dict, which is contained in the internal thread state structure.</p>
<dl class="cfunction">
<dt id="PySys_GetObject">
<a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a> *<tt class="descname">PySys_GetObject</tt><big>(</big>char<em> *name</em><big>)</big><a class="headerlink" href="#PySys_GetObject" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the object <em>name</em> from the <a title="Access system-specific parameters and functions." class="reference external" href="../library/sys.html#module-sys"><tt class="xref docutils literal"><span class="pre">sys</span></tt></a> module or <em>NULL</em> if it does
not exist, without setting an exception.</p>
</dd></dl>

<dl class="cfunction">
<dt id="PySys_GetFile">
FILE *<tt class="descname">PySys_GetFile</tt><big>(</big>char<em> *name</em>, FILE<em> *def</em><big>)</big><a class="headerlink" href="#PySys_GetFile" title="Permalink to this definition">¶</a></dt>
<dd>Return the <tt class="xref docutils literal"><span class="pre">FILE*</span></tt> associated with the object <em>name</em> in the
<a title="Access system-specific parameters and functions." class="reference external" href="../library/sys.html#module-sys"><tt class="xref docutils literal"><span class="pre">sys</span></tt></a> module, or <em>def</em> if <em>name</em> is not in the module or is not associated
with a <tt class="xref docutils literal"><span class="pre">FILE*</span></tt>.</dd></dl>

<dl class="cfunction">
<dt id="PySys_SetObject">
int <tt class="descname">PySys_SetObject</tt><big>(</big>char<em> *name</em>, <a title="PyObject" class="reference external" href="structures.html#PyObject">PyObject</a><em> *v</em><big>)</big><a class="headerlink" href="#PySys_SetObject" title="Permalink to this definition">¶</a></dt>
<dd>Set <em>name</em> in the <a title="Access system-specific parameters and functions." class="reference external" href="../library/sys.html#module-sys"><tt class="xref docutils literal"><span class="pre">sys</span></tt></a> module to <em>v</em> unless <em>v</em> is <em>NULL</em>, in which
case <em>name</em> is deleted from the sys module. Returns <tt class="docutils literal"><span class="pre">0</span></tt> on success, <tt class="docutils literal"><span class="pre">-1</span></tt>
on error.</dd></dl>

<dl class="cfunction">
<dt id="PySys_ResetWarnOptions">
void <tt class="descname">PySys_ResetWarnOptions</tt><big>(</big>void<big>)</big><a class="headerlink" href="#PySys_ResetWarnOptions" title="Permalink to this definition">¶</a></dt>
<dd>Reset <a title="sys.warnoptions" class="reference external" href="../library/sys.html#sys.warnoptions"><tt class="xref docutils literal"><span class="pre">sys.warnoptions</span></tt></a> to an empty list.</dd></dl>

<dl class="cfunction">
<dt id="PySys_AddWarnOption">
void <tt class="descname">PySys_AddWarnOption</tt><big>(</big>char<em> *s</em><big>)</big><a class="headerlink" href="#PySys_AddWarnOption" title="Permalink to this definition">¶</a></dt>
<dd>Append <em>s</em> to <a title="sys.warnoptions" class="reference external" href="../library/sys.html#sys.warnoptions"><tt class="xref docutils literal"><span class="pre">sys.warnoptions</span></tt></a>.</dd></dl>

<dl class="cfunction">
<dt id="PySys_SetPath">
void <tt class="descname">PySys_SetPath</tt><big>(</big>char<em> *path</em><big>)</big><a class="headerlink" href="#PySys_SetPath" title="Permalink to this definition">¶</a></dt>
<dd>Set <a title="sys.path" class="reference external" href="../library/sys.html#sys.path"><tt class="xref docutils literal"><span class="pre">sys.path</span></tt></a> to a list object of paths found in <em>path</em> which should
be a list of paths separated with the platform&#8217;s search path delimiter
(<tt class="docutils literal"><span class="pre">:</span></tt> on Unix, <tt class="docutils literal"><span class="pre">;</span></tt> on Windows).</dd></dl>

<dl class="cfunction">
<dt id="PySys_WriteStdout">
void <tt class="descname">PySys_WriteStdout</tt><big>(</big>const char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PySys_WriteStdout" title="Permalink to this definition">¶</a></dt>
<dd><p>Write the output string described by <em>format</em> to <a title="sys.stdout" class="reference external" href="../library/sys.html#sys.stdout"><tt class="xref docutils literal"><span class="pre">sys.stdout</span></tt></a>.  No
exceptions are raised, even if truncation occurs (see below).</p>
<p><em>format</em> should limit the total size of the formatted output string to
1000 bytes or less &#8211; after 1000 bytes, the output string is truncated.
In particular, this means that no unrestricted &#8220;%s&#8221; formats should occur;
these should be limited using &#8220;%.&lt;N&gt;s&#8221; where &lt;N&gt; is a decimal number
calculated so that &lt;N&gt; plus the maximum size of other formatted text does not
exceed 1000 bytes.  Also watch out for &#8220;%f&#8221;, which can print hundreds of
digits for very large numbers.</p>
<p>If a problem occurs, or <a title="sys.stdout" class="reference external" href="../library/sys.html#sys.stdout"><tt class="xref docutils literal"><span class="pre">sys.stdout</span></tt></a> is unset, the formatted message
is written to the real (C level) <em>stdout</em>.</p>
</dd></dl>

<dl class="cfunction">
<dt id="PySys_WriteStderr">
void <tt class="descname">PySys_WriteStderr</tt><big>(</big>const char<em> *format</em>, ...<big>)</big><a class="headerlink" href="#PySys_WriteStderr" title="Permalink to this definition">¶</a></dt>
<dd>As above, but write to <a title="sys.stderr" class="reference external" href="../library/sys.html#sys.stderr"><tt class="xref docutils literal"><span class="pre">sys.stderr</span></tt></a> or <em>stderr</em> instead.</dd></dl>

</div>
<div class="section" id="process-control">
<span id="processcontrol"></span><h1>Process Control<a class="headerlink" href="#process-control" title="Permalink to this headline">¶</a></h1>
<dl class="cfunction">
<dt id="Py_FatalError">
void <tt class="descname">Py_FatalError</tt><big>(</big>const char<em> *message</em><big>)</big><a class="headerlink" href="#Py_FatalError" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-145">Print a fatal error message and kill the process.  No cleanup is performed.
This function should only be invoked when a condition is detected that would
make it dangerous to continue using the Python interpreter; e.g., when the
object administration appears to be corrupted.  On Unix, the standard C library
function <tt class="xref docutils literal"><span class="pre">abort</span></tt> is called which will attempt to produce a <tt class="docutils literal"><span class="pre">core</span></tt>
file.</p>
</dd></dl>

<dl class="cfunction">
<dt id="Py_Exit">
void <tt class="descname">Py_Exit</tt><big>(</big>int<em> status</em><big>)</big><a class="headerlink" href="#Py_Exit" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-146">Exit the current process.  This calls <a title="Py_Finalize" class="reference external" href="init.html#Py_Finalize"><tt class="xref docutils literal"><span class="pre">Py_Finalize</span></tt></a> and then calls the
standard C library function <tt class="docutils literal"><span class="pre">exit(status)</span></tt>.</p>
</dd></dl>

<dl class="cfunction">
<dt id="Py_AtExit">
int <tt class="descname">Py_AtExit</tt><big>(</big>void (*func)<em> ()</em><big>)</big><a class="headerlink" href="#Py_AtExit" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-147">Register a cleanup function to be called by <a title="Py_Finalize" class="reference external" href="init.html#Py_Finalize"><tt class="xref docutils literal"><span class="pre">Py_Finalize</span></tt></a>.  The cleanup
function will be called with no arguments and should return no value.  At most
32 cleanup functions can be registered.  When the registration is successful,
<a title="Py_AtExit" class="reference internal" href="#Py_AtExit"><tt class="xref docutils literal"><span class="pre">Py_AtExit</span></tt></a> returns <tt class="docutils literal"><span class="pre">0</span></tt>; on failure, it returns <tt class="docutils literal"><span class="pre">-1</span></tt>.  The cleanup
function registered last is called first. Each cleanup function will be called
at most once.  Since Python&#8217;s internal finalization will have completed before
the cleanup function, no Python APIs should be called by <em>func</em>.</p>
</dd></dl>

</div>


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<li><a class="reference external" href="">Operating System Utilities</a></li>
<li><a class="reference external" href="#system-functions">System Functions</a></li>
<li><a class="reference external" href="#process-control">Process Control</a></li>
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